1. Field of the Invention
This invention relates to a photocurable and thermosetting resin composition which is usable in various application fields such as a solder resist and an etching resist to be used in the production of a printed circuit board, an interlaminar insulating material for a build-up circuit board, a plating resist, a photosensitive dry film, and the production of a fluorescent material for PDP (plasma display panel), specifically a photocurable and thermosetting resin composition which is developable with an aqueous alkaline solution and capable of producing a coating film excelling in resistance to heat, adhesiveness, etc.
2. Description of the Prior Art
In the soldering process which is carried out in mounting electronic parts on a printed circuit board, a solder resist is used for the purpose of preventing molten solder from adhering to irrelevant portions and protecting circuits. In recent years, a developing type solder resist which is used to form a pattern by a photolithographic method is widely adopted. Particularly, with due respect to the problem of environmental safety and from the viewpoint of cost, the solder resist of the alkali developing type has come to play the leading role. As a base resin used for these developing type solder resists, an actinic energy ray-curable resin obtained by reacting an epoxy resin with (meth)acrylic acid and subsequently reacting an acid anhydride with the resultant hydroxyl group of the modified resin is generally used.
Meanwhile, in consequence of the trend of IC and LSI parts toward highly dense mounting, the necessity of decreasing the width of circuit lines and the intervals between circuits of the printed circuit boards has been finding growing recognition. Besides, since the operating frequency of these parts to be mounted is enhanced, the heat value released from these parts increases accordingly. Therefore, the printed circuit board tends to require high thermal stability more than desired heretofore. In the actinic energy ray-curable resin obtained by using an epoxy resin as a starting raw material, however, since most of the functional groups which bond to an acid anhydride are secondary hydroxyl groups, the resin has the problem of relatively easily suffering the breakage of bonds when exposed to an increased temperature for a long time and, as result, inducing the possibility of degradation of such properties as insulation properties and resistance to heat and contamination of circuits due to the scattering of the decomposed acid anhydride.
In recent years, from the viewpoints of creation of a new organic reaction and its application to the synthesis of macromolecular compounds, the organic reaction involving the ring opening addition reaction of an oxetane ring which is an ether of four-membered ring has been studied. For example, the addition reaction of an oxetane compound and an active ester (T. Nishikubo and K. Sato, Chem. Lett., 697 (1992)) and the synthesis of polyester having a primary hydroxyl group attached to a side chain thereof by the polyaddition reaction of a bisoxetane and a dicarboxylic acid (T. Nishikubo, A. Kameyama, and A. Suzuki, Reactive & Functional Polymers, 37, 19 (1998)) have been studied and reported. Further, the polyaddition reaction of a bisoxetane and a bisphenol has been reported recently (T. Nishikubo, A. Kameyama, M. Ito, T. Nakajima, and H. Miyazaki, Journal of Polymer Chemistry, Vol. 37, pp. 2781-2790(1998)) and tetraphenyl phosphonium bromide (TPPB) etc. are used as a reaction catalyst. However, these published articles make no mention of an actinic energy ray-curable resin of the present invention and a photocurable and thermosetting resin composition using the same.